Hi Fred,
I vented the tank to the neck since I was unhappy with the standard vent
arrangement. The main problem I found was that the vent tube from the
tank was too small and caused the fill pipe to back up and burp at low
fill rates from a hose. The vent pipe also vented fuel onto the top of
the fuselage. The changes I made have worked out well and consist of the
following steps :-
* Modified the vent fitting at the tank so that I could use a larger
vent tube size (clear plastic tubing with fabric reinforcement,
3/8" dia I think. I can check if you wish).
* Installed a tee fitting at the top neck of the filler. This was
bonded into place with Redux.
* The center leg of the tee is connected into the filler neck which
was drilled to suit. One other leg is connected to the tank vent
tubing and the third leg is sized for the original small tubing
and goes directly to the vent on the fuselage top.
* Another feature which helps during filling is that I have a 2"
section in the middle of the fuel down pipe which is left
unpainted. This makes it easy to check filling progress. I can now
fill at basically the full flow rate and I do not get any fuel
vented onto the fuselage top.
I do not use a sight gauge arrangement. I have two capacitance fuel
gauges plus my Grand Rapids EIS flowmeter and totaliser.
Cheers, John
N262WF, mono XS, 912S
Mooresville, North Carolina
ORIGINAL MESSAGE
Subject: Europa-List: Fuel venting
From: Fred Klein <fklein@orcasonline.com>
I understand that some builders have vented the tank and the sight
gauge to the top of the fuel filler pipe, taking care that the precise
location will not allow fuel being added to inadvertantly flow into the
vents. What I don't understand is...using the supplied fuel filler cap
(which is specifically called out as "non-venting", again in the ACS
catalogue)...how such an arrangement in fact can act to vent the fuel
system.
Can anyone enlighten me?
Fred
|